Combination centering, focusing, and deflecting device for beam of cathode-ray tubes



March 13, 1951 A. J, BENNETT 2,544,875

COMBINATION CENTERING', FOCUSING, AND DEELECTING DEVICE FOR BEAM OF CATHODE-RAY TUBES Filed April l5, 1950 Patented Mar. 13, 1951 COMBINATION CENTERING, FQCUSING, AND DEFLECTING DEVICE FOR BEAM OF CATHODE-RAY TUBES Arthur James Bennett, Cambridge, England, `asi-- signor to Pye Limited, Cambridge, England, a

British company Application April 15, 1950., Serial No. 156,225 In Great Britain MarchfZ, 1950 2 Claims. 1

This invention relates to a combination centering, focusing and deflecting device for cathode ray'tubes and to a means of assembling them into a unitary structure and mounting them relative to the neck of a cathode ray tube in proper position.

It has heretofore been common practice to provide a focusing coil and a deflecting coil on the neck of cathode ray television tubes for focusing vand directing the beam thereof. A new principle and device has been discovered for centeringthe beam of a cathode Yray tube for use in television receivers. This principle and device are described in the copending applications of Patrick Richard James Court Serial No. 144,688 led February 17th, 1950 for Beam Centering Devices for Cathode Ray Tubes and of Thedore Obszarny and John Schmidt, Serial No. 136,294 filed December 31,1949 for Centering Device for Beam of` Cathode Ray Tubes.

The new centering device comprises a pair of permanent magnets which are mountedl about the neck of the cathode ray tube and which are rotatably .adjustable relatively to each other and the neck of the tube in order that the electrical field of the beam or cathode ray may be biased in any desired direction,in order to center,` the ray with respect to the uorescent material on the front of the tube. This invention, however, relates pri-marily to providing a unitary assembly ior a centering device of the type described, a focus coil and a .deflecting coil, and one of vits objects is to provide such an assembly which is inexpensive and readily mountable with .respect to the cathode tube.

It is another object of therinvention to provide a common mounting member on which the centering device, the focus coil and the .deiiecting coilsv are mounted.

It is a further object of the invention to provide a unitary structure for the centering device, focus coil and deflecting coils which is partially encased and is pleasing in appearance aswell as being readily mountable.

With these and other objects in View, my invention consists in the construction, arrangement and combination of the various parts of my device whereby the objects contemplated are attained as hereinafter more fully set forth, pointed out in my claims, and illustrated in the accompanying drawings, in which:

Figure 1 is a view of the improved unitary structure including the centering device, focus coil and deflecting coils, together with its mounting, with the cathode ray tube shown diagrammatically;

Figure 2 is a sectional view of the unitary device taken on line 2-2 of Figure 1;

Figure 3 is an end view of the unitary device taken from the focusing coil end, with parts thereof broken away; and

Figure 4 is a sectional v-iew of the centering device taken on line 4-4 of Figure 2.

Referring specically to the drawings for a detailed description of the invention, numeral II designates generally a cathode ray tube for television sets which is provided with a neck I2 and a plug I3. The unitary assembly of centering device I5, focus coil `I6 and deilecting coils Il, is shown generally at I4.

The centering device I5 includes a pair o f insulating rings I8 and I9 which are identical in shape. The ring I8 carries a permanent magnet 2jI in the shape of a broken ring having a north pole at the point marked N and a south pole at the point marked S in Figure 4. An identical permanent magnet 22Y is positioned on the ring I9. AnV insulating ring 20 separates the two magnets. The ring I5 is provided with a pair of opposed` tabs 30, the lower one of which has an aperture 23 therein. The ring I9 is likewise provided with a pair oijopposed` tabs 39, the lower one ofv which is provided' with an aperture 24. The rings I8 and I9, with the electrom-agnets ZI and 22, maybe rotated to any position and may be rotated relatively to each other to center the cathode ray beam. The apertures 23 and 24 in the tabs 38, shown at the lower part of Figure 2, may be used as indicia to indicate the relative position of the electromagnets and the intensity and direction of the combined magnetic elds of the two electromagnets.

The focus coil I6 comprises an outer electromagnet Vring 25 vand an inner energ-izable core 26 and is constructed in a. manner Well understood in the art.

Thedeecting coils II comprise Vertical deilecting coils 21 and 28 and horizontal deilecting coils29 and 3 I. They are surrounded and maintained together by the coil 32 of magnetic material in a manner well understood in the art. An insulating disk 4I) is disposed between the focus coil I6 and the deflecting coil I'I, as it is preferable to magnetically insulate these two coils from each other for proper operation.

The centering device I5, the focus coil I6 and deflecting coils generally indicated at I'I are all mounted on an electrically insulating tube 33 formed, for example, of cardboard. The tube 33 has an edge 34 which is spun over to retain one end of the parts in position and has another opposite edge 35 which may be glued to the 3 deecting coils, or secured thereto in any desired manner.

It will be noted that the rings I8 and I9 of the centering device =I5 are mounted directly on the tube 33 and are rotatable thereon to any desired position or relatively to each other.

The magnetic eld of the two magnets ZI and,- -A 22 may, therefore, be varied and react on the M cathode ray electromagnetic field in a manner so as to bias it in any desired direction and thus move the cathode ray so that it will be centered. The purpose and operation of the focus coil I6 and the deilecting coils I'I are well understood in the art and no further explanation of them is believed to be necessary.

The focus coil I6 and the most of the area of delecting coils II are enclosed in a'cylindrical telescoping casing, one part of which islshown at 45 and the other part at 46. The centering device I5 is not enclosed within the casing 45 and 46, since it must be adjusted from an accessible position. An aperture lll is provided in the top of the casing portion 46 and an inverted U-shaped member extends therethrough. A metal strap 3B surrounds the deilecting coils il and hooks into the member 38, as shown at 3l. A wing nut y4I is adapted to be threaded into a threaded aperture 39 in the top of the member 38. Supporting posts 4d are provided in the chassis of vthe television set (not shown) and a strap 42 extends therebetween having a suitable opening adjacent the center thereof through which the wing nut 4I extends. The strap 42 is secured :to the supports lili by screws 43.

The entire assembly it may, therefore, be slid over the neck l2 of the cathode ray television tube lI and positioned thereon wherever desired. 'The combined unit i4 is supported mainly from the strap d2 and supports 44 and, therefore, it :does not necessarily contact the neck I2 of the cathode ray television tube II, whereby damage or implosion to the neck is minimized.

From the foregoing it will be apparent that have provided an improved unitary structure in which a common supporting member is utilized for supporting and positioning a centering device, a focus coil and delecting coils for a television cathode ray tube. 1t also provides a bearing affording rotation of themagnets of the centering device to any desired position. A,

Some changes may be made in the construction and arrangement of the parts of my device without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claims any modified forms of structure and use of mechanical equivalents which may be reasonably included within their scope without sacricing any of the advantages thereof.

I claim as my invention:

1. A unitary centering, focusing, and deilecting apparatus for a cathode ray tube comprising in combination, an elongated circular sleeve adapted to receive the neck of a cathode ray tube and having an outer annular shoulder at one end,

`4 a ray beam centering unit comprising a series of disks between which are sandwiched ray beam centering magnets, the disks being snugly but rotatably Vreceived on the sleeve and bottoming against the shoulder thereof, the disks being operable when rotated relativ-e to the sleeve to -control the position of the ray beam in relation to the center of the viewing screen, a cup mem- 'bersnugly rreceived on the sleeve in abutting relation to the centering unit, a focusing unit received within the connes of the cup member and abutting the end face thereof, a deflecting unit snugly received upon and anchored to the sleeve adjacent the focusing unit, the deflecting unit having an outer sleeve in telescopic relation tothe cup and a support member adap-ted to be received on a supporting bracket to sustain the entireunit in position.

2. A unitary centering, focusing, and deilecting apparatus for a cathode ray tube comprising in combination, an elongated circular sleeve adapted to receive the neck of a cathode ray tube and having an outer annular shoulder at one end, a ray beam centering unit comprising a series of disks between which are sandwiched ray beam centering magnets, the disks being snugly but rotatably received on the sleeve and bottoming against the shoulder thereof, the disks being operable when rotated relative to the sleeve to control the position of the ray beam in relation to the center of the viewing screen and having axially extending handles for manual adjustment, a cup member snugly received on the sleeve in abutting relation to the centering unit, a focusing unit received within the connes of the cup member and abutting the end face thereof, a

-deflecting unit snugly received upon and an- .chored to the sleeve adjacent the focusing unit,

the deilecting unit having an outer sleeve in telescopic relation to the cup and a support mem- .ber adapted to vbe received on a'supporting bracket to sustain the entire' unit in position.

ARTHUR JAMES BENNETT.

REFERENCES CITED The following references are of record in the leof this patent:

UNITED STATES PATENTS Number Name Date 2,102,421 Kuehni Dec. 14, 1937 V2,207,777 Blain July 16, 1940 2,234,720 DeTar Mar. 11, 1941 2,336,837 Bedford Dec. 14, 1943 2,433,682 Bradley Dec. 30, 1947 2,443,025 DeTar June 8, 1948 2,456,474 Wainwright Dec. 14, 1948 2,501,516 Holden Mar. 21, 1950 FOREIGN PATENTS Number Country Date 464,637 Great Britain Apr. 21, 1937 

